Here is the situation. I have a 2006 GTO (stock) that I am installing a turbocharger on. It is a MP T70 w/ .96 AR. My goal now is to run 5-7psi w/ intercooler. So far I have Siemens Deka 60's and I plan to get a performance fuel pump. I know I can pretty much get away with that for my fuel system with my current power goals. I intend on running the custom 2-bar SD tune. I have a couple scenarios that I am considering.
1) Slap in the injectors and pump, set the IFR to 63.5 across the board and enter other injector data (short PW adder, min inj PW,ect). Then start to tune and proceed to, from what I have come to understand, “rape my tune”. I understand this this not the recommended method but is somewhat common. Especially at my power level.
2) The next option would be to do the same as above with the exception of just throwing in 63.5. Instead scale my tune for the 60’s by working over all the tables’ air flow and get the proper values in my IFR vs. Kpa table. This should prevent drivability issues because I can address the injector change across all the tables that use it, instead of just changing a few to “make it run”.
3) Buy some fuel rails, install referenced regulator (already have one) run a return to the tank and dial back my fuel pressure to 48 psi or so (can remember exactly I figured it out at one point). Bringing the injectors flow rate down to the IFR ceiling of 63.5 then put that value in my IFR vs. Kps table across the board. Then work over the rest of the injector settings until the car drives like stock out of boost. I am assuming with the correct injector data and keeping the IFR under the limit, the new bigger injectors should “act” just like the stock ones. Then I can move into tuning the boost or power enrichment side then timing.
I am leaning towards option 3 primarily because scaling to me seems a little overwhelming! I think I get it but I feel like I am likely to miss something but I suppose if you take your time and open up every single table then double check everything it shouldn’t be so bad. The other reason I like option 3 is that it is just plain better, easier to tune and allows more room to grow. Although, I don’t want to go through all the extra work and expense if it’s just not necessary.